An absorptive readout technique for beam addressed optical memory

The original concept for digital optical memory envisaged a random access, beam addressable system. However, to facilitate the rapid development of write-once (WORM) and rewritable thermo-magneto-optic optical storage products, it was expedient to adopt the rotating disk format together with the servo control and access systems that had already been brought to a high level of refinement by the magnetic recording industry. Whilst the performance of present disk servo systems is undoubtably impressive, there must inevitably come a time, as processor speeds continue to increase and electronic processors are superseded by optical equivalents, when mechanical servo systems severely limit the ultimate performance of a data processing system. To address this issue we have considered some of the problems inherent in beam addressed systems by investigating the use of media developed for the current generation of disk based WORM and MO recording systems in a beam addressable format.